| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit whose limit of an output signal amplitude is high under the condition of low voltage power supply, in a voltage-current conversion circuit for eliminating an in-phase component of an input voltage. SOLUTION: When input voltages to voltage-current conversion circuits Gm1 and Gm2 are set to V1 and V2 and differential components of the input voltages are set to 2Vin and in-phase components of the input voltages is set to Vcm, V1=Vin+Vcm, V2=-Vin+Vcm. When potential on a line to which 4 terminals of in2 and Out2 of Gm1 and Gm2 is set to Va, an output current is represented by I1=-Gm(V1+Va), I2=-Gm(V2+Va). Since the input impedance of Gm1 and Gm2 are extremely large, the current fed back can flow into neither of reverse-phase input terminals in2 of Gm1 nor Gm2, thus, it becomes I1+I2=0. That is, feedback for offsetting the in-phase component is applied to the reverse-phase input terminals in2, the in-phase component is eliminated from the output current. COPYRIGHT: (C)2007,JPO&INPIT
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